Size comparison: Moon vs Triton

Size comparison between our satellite the Moon and the natural satellite of Neptune: Triton.

Triton is the largest natural satellite in the solar system after the Moon, with a diameter greater than that of Pluto. It is assumed that Triton is an ancient dwarf planet that was captured by the Kuiper Belt. The surface of this Moon is mostly made up of frozen nitrogen, with water ice. Voyager 2 is the only ship to have visited Triton. The geology of this body is active, which is why there are few visible craters.

Object	Moon	Triton
Type	Rocky satellite	Rocky satellite
Age	4.53 billion years	4.53 billion years
Diameter	3,474 km	2,706 km
Mean radius	1,737 km	1,353 km
Mass	7.34 × 1022 kg	2.13 × 1022 kg
Orbital period	27 days	5.87 days
Surface temperature (average)	220 K -53 °C -63 °F	38 K -235.2 °C -391.3 °F
Surface gravity	1.6 m/s²	0.77 m/s²
Mean density	3.3 g/cm3	2.06 g/cm3
Orbital distance	384,402 km	354,759 km
Circumference	10,921 km	8,501 km
Surface area	37 million km²	37 million km²
Volume	2.19 × 1010 km3	2.3 × 107 km3
Escape velocity	2.3 km/s	1.45 km/s
Average orbital speed	1.02 km/s	4.39 km/s
Semi major axis	384 thousands km	354 thousands km
Inclination	5.1°	129.8°
Surface pressure	10−7 Pa	1.4 Pa
Atmosphere composition	argon, helium, neon	nitrogen, methane
Crust composition	45% silica, 19% alumina, 14% lime, 10% iron, 2% titanium dioxide, 0.6% sodium oxide	55% nitrogen ice, 35% water ice, 10% frozen carbon dioxide, rock, metal
Distance from the Milky Way center	27,200 light years	27,200 light years

Note: if one of the objects is not visible, it just means that it is too tiny to be displayed compared to the other one.